Analysis of insulation coordination for dual motion mechanism gas circuit breaker

In this paper, we propose the technology to analyze the insulation coordination for dual motion mechanism (DMM) gas circuit breaker (GCB). To estimate the insulation level of SF₆ gas in GCB, we calculate the permitted electric field strength in accordance with the SF₆ gas pressure. Through an electric field simulation along the dual motion travel, we estimate the insulation performance of GCB. We control the delay time of the second moving part travel for insulation coordination. As a case study, we analyze the electric field simulation along the dual motion travel about three kinds of delay times for the second moving part of 420kV GCB model.